Numerous innovations for adjustable stairways have been provided in the prior art that are described as follows. Even though these innovations may be suitable for specific individual purposes to which they address, they differ from the present invention as hereinafter contrasted.
The prior art does not utilize a pivoted motion and does not allow an infinite amount of variable spacings when framing stairs and/or a railing. The present invention allows an infinite amount of variable spacings and use of a pivoting motion.
U.S. Pat. No. 2,245,825 to W. E. Ross teaches a folding stand that has pivoting support but is not based on vertical holes which keep treds in a horizontal position with an infinite amount of variable spacings. Furthermore, the patented invention utilizes different elements from the present invention. Some of the differences are:
1) Vertical holes are not important,
2) Stair is adjustable into one position only,
3) Not meant to be permanently fixed after moved into position on risers,
4) Risers and treds to not slide past each other,
5) Pivoting tred support is not fixed in position after adjustment and therefore not used to lock stringers.
U.S. Pat. No. 4,370,664 to J. J. Whitehead teaches an adjustable staircase. The patented invention does not have any pivoting motion and utilizes different elements from the present invention.
U.S. Pat. No. 3,885,365 to J. W. Cox teaches a self adjusting stair which utilizes a truss assemblage. In the patented invention adjustments are made using a pin and slot. The patented invention does not utilize any pivoting motion and the rails are not adjusted by stringers as with the present invention.
U.S. Pat. No. 3,962,838 to J. W. Cox teaches a self adjusting stair which utilizes spacers in a truss assemblage. The patented invention does not utilize a pivoting motion and the rails are not adjusted by stringers.
U.S. Pat. No. 4,406,347 to N. M. Strathopoulos teaches a modular staircase assembly. The patented invention does not utilize a pivoting motion. The rails are not adjusted by stringers and are not adjusted on vertical holes.
U.S. Pat. No. 4,959,935 to H. R. Stob teaches a prefabricated adjustable stairway. The patented invention does not utilize a pivoting motion and the rails are not adjusted by stringers. This apparatus uses a three point pivoting action so that stringers do not separate during adjustment and slide one on top of the other.
U.S. Pat. No. 5,189,854 to K. J. Nebel teaches an adjustable height staircase. The patented invention does not utilize a pivoting apparatus as described herein. The present invention utilizes a pivoting apparatus and contains different elements from the patented invention for at least the following reasons:
1) Treds are directly connected to stringers,
2) No risers,
3) No sliding motion of riser past the tred.
U.S. Pat. No. 4,124,957 to Pouplaw shows treds that are directly connected to stringers, stringers that have special tongue and groove spacers which must be an exact size each time in order to lock stringers otherwise the stringers must be secured top and botton of the stair only, and risers and treds do not slide past each other.
Numerous innovations for adjustable staircases have been provided in the prior art that are adapted to be used. Even though these innovations may be suitable for specific individual purposes to which they address, they would not be suitable for the purposes of the present invention as heretofore described.
The structure of the present invention can be used for forming a stair and may also be used as a support for concrete form work, as a form for a ramp, as a form for adjustable shelves, as an adjustable bleacher, and for adjustable displays.
It is an object of the present invention to provide an adjustable stringer and railing that allows users to have a quickly formed stair structure.
It is another object of the present invention to provide an adjustable stringer and railing that provides partially assembled elements that can be adjusted to a variety of applications and then securely fixed to form a stair framing and/or railing framing.
It is another object of the present invention to provide an adjustable stringer and railing that utilizes a pivoting motion.
It is another object of the present invention to provide an adjustable stringer and railing that allows an infinite amount of variable spacings when creating stairs and/or railing.
It is another object of the present invention to provide an adjustable stringer and railing that eliminates the need to calculate spacing between step treds and angle of the stairs.
It is another object of the present invention to provide an adjustable stringer and railing that provides an embodiment that includes an upper stringer arm, a lower stringer arm and at least one riser support.
It is another object of the present invention to provide an adjustable stringer and railing that provides an embodiment that includes an upper rail support and at least two railing posts pivotally attached to the upper rail support.
It is another object of the present invention to provide an adjustable stringer and railing that is easy and inexpensive to manufacture.
Another object of the present invention is the use of a bracket and setting and spacer bar that can be used with stringer elements for simplifying the formation of a stair assembly with treds, risers and rail supports.
Further objects of the present invention include a stair forming apparatus that includes a pivoting block to which treds and risers can be attached, a pivoting block to which treds only can be attached, a pivoting block which allows risers and treds to slide past each other, a pivoting block which allows risers and treds to be attached such that the risers and treds can be attached to each other after assembly to form a solid construction in which the risers become beams and the treds become lateral bracing to produce great structural stength and much wider stair widths than normal with on center supports (additional stringers) as with normal stairs, and greater stringer strength than with normal saw tooth stringers because of greater stringer depth and, when the riser/tred supports are secured to the upper and lower stringers after adjustment, the stringers are bonded together to form one solid stringer which also is capable of much greater spans without additional supports.
The structure of the present invention includes riser and tred support which allows risers and tred to slide past each other (as the stinger is adjusted) in order to utilize standard lumber and eliminate the need to cut lumber to exact widths, to use standard lumber of varing lengths according to width of the stair (i.e. 4xe2x80x2 to 10xe2x80x2 wide stairs), to use riser and tred support systems which, after pivoting and adjusting in position, allows risers to be used as beams which greatly increases the structural strength of the stair allowing much greater stair widths than normal without the need for additional center support stringers, and provides a stringer system which, when the riser/tred supports are secured, the stringer members are bonded together to form a much stronger stringer member than in normal xe2x80x9csaw toothxe2x80x9d type construction giving much greater stair lengths without additional supports.
The foregoing benefits are accomplished with the use of a simplified bracket, spacer and setting combination that permits the assembly of a stair stringer assembly without difficulty permitting the xe2x80x9cdo it your-selferxe2x80x9d to install a stair assembly with simple instructions.